Dexmedetomidine Produces Dual α2-Adrenergic Agonist and α1-Adrenergic Antagonist Actions on Human Isolated Internal Mammary Artery
Journal of Cardiothoracic and Vascular Anesthesia, cilt.21, sa.5, ss.696-700, 2007 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 21 Sayı: 5
- Basım Tarihi: 2007
- Doi Numarası: 10.1053/j.jvca.2006.11.005
- Dergi Adı: Journal of Cardiothoracic and Vascular Anesthesia
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.696-700
- Anahtar Kelimeler: dexmedetomidine, contraction, alpha-adrenoceptors, human internal mammary artery
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Objective: To investigate the direct effects of dexmedetomidine (DEX) on isolated human internal mammary artery (IMA). Design: In vitro experimental study. Setting: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Gulhane School of Medicine, Ankara, Turkey. Participants: IMA segments were obtained from 18 patients undergoing coronary artery bypass surgery. Interventions: The response in IMA was recorded isometrically by a force displacement transducer in isolated organ baths. DEX-induced contractions were tested in the presence of the α2-adrenoceptor antagonist yohimbine (10-7 mol/L) and the α1-adrenoceptor antagonist prazosin (10-8 M). The effect of DEX (10-7, 10-6, and 10-5 mol/L) on phenylephrine (10-9-3 × 10-4 mol/L)-induced contactions was also tested. Measurement and Main Results: DEX (10-9 mol/L-3 × 10-5 mol/L) caused contraction in IMA segments. The contraction at lower concentrations of DEX (10-9 mol/L-3 × 10-7 mol/L) was attenuated by yohimbine (10-7 mol/L), whereas prazosin (10-8 mol/L) attenuated the contractions at higher concentrations of DEX (10-6 mol/L-3 × 10-5 mol/L). Incubation of IMA segments with high concentrations of DEX (10-6 mol/L and 10-5 mol/L) caused an inhibition of phenylephrine (10-9 mol/L-3 × 10-4 mol/L)-induced contraction. Conclusion: These data suggest that DEX causes contraction by activating α2-adrenoceptors at lower concentrations, but it may also activate α1-adrenoceptors at higher concentrations in IMA. The action of DEX on phenylephrine-induced contraction may be related to an α1-adrenoceptor antagonistic effect produced via partial α1-adrenoceptor agonistic action. © 2007 Elsevier Inc. All rights reserved.